Endoscopic surgical device and outer sleeve

ABSTRACT

Provided is an endoscopic surgical device and an overtube with which a surgeon can easily obtain a desired image and operability is high. The overtube includes a slider inside the overtube body that guides an endoscope and a treatment tool into a body cavity, the first valve member provided in the endoscope insertion passage, and the second valve member provided in the treatment tool insertion passage. F1&gt;F3 and F2&gt;F3 are satisfied when a fixing force for fixing the slider to the endoscope is defined as F1, a fixing force for fixing the slider to the treatment tool is defined as F2, and a frictional force that receives from the first valve member when the endoscope moves forward and backward is defined as F3.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a Continuation of and claims the prioritybenefit of U.S. application Ser. No. 15/058,096, filed on Mar. 1, 2016,now allowed, which is a Continuation of PCT International ApplicationNo. PCT/JP2014/072994 filed on Sep. 2, 2014 claiming priority under 35U.S.C. § 119(a) of U.S. Provisional Application No. 61/873,113 filed onSep. 3, 2013. Each of the above applications is hereby expresslyincorporated by reference, in their entirety, into the presentapplication.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to an endoscopic surgical device and anovertube (outer sleeve), and particularly, relates to an endoscopicsurgical device and an overtube that can operate in a state where anendoscope and a treatment tool inserted into a body cavity areinterlocked with each other.

2. Description of the Related Art

In the related art, the endoscopic surgery of inserting a treatment tooland an endoscope into a patient's body cavity and performing treatmentwork while observing, using the endoscope, the treatment state of anaffected part using the treatment tool inserted into the body cavity hasbeen known. In this surgery, in order for a surgeon to obtain a visualfield where surgery is easy, the operation of changing the observationposition of the endoscope is performed when necessary.

Generally, in the endoscopic surgery, a surgeon's hand is blocked due tothe operation of the treatment tool, and the operation of changing theobservation position of the endoscope is performed by an assistantcalled a scopist (endoscopic technician). For this reason, when theobservation position of the endoscope is changed, the surgeon shouldserially give instructions to the assistant. Therefore, the work ofcorrectly directing the orientation of the endoscope to a directiondesired by the surgeon is difficult, and stress is likely to be imposedon the surgeon. Additionally, since the assistant performs an operationafter the surgeon issues an instruction, there is a tendency thatsurgery time is likely to be prolonged. Additionally, the assistantshould operate the endoscope so as not to interfere with a surgeon'sprocedure, and the operation is likely to become complicated.

In contrast, for example, an endoscopic surgery system, which moves thetreatment tool while following the fluctuation of the visual field ofthe endoscope for the purpose of smoothly performing endoscopic surgery,is disclosed in JP2004-141486A. In this endoscopic surgery system, atreatment part of the treatment tool is kept from deviating from thevisual field of the endoscope by detecting the movement distance (therotational angle and the amount of insertion and extraction) of theendoscope in a state where the endoscope and the treatment tool havebeen inserted into an integral sheath (guide member), and controllingthe movement distance (the rotational angle and the amount of insertionand extraction) of the treatment tool with respect to the sheath on thebasis of the detection result.

Additionally, an endoscopic surgery device that changes the visual fieldof the endoscope while following the movement of the treatment toolinserted into the body cavity during the endoscopic surgery is disclosedin JP2003-325436A. This endoscopic surgery device is provided bymechanically coupling the treatment tool to a distal end part of theendoscope to integrally move the treatment tool and the distal end partof the endoscope to move the observation optical axis of the endoscopein a direction in which the treatment tool moves.

SUMMARY OF THE INVENTION

However, the endoscopic surgery system disclosed in JP2004-141486A doesnot mechanically interlock the endoscope with the treatment tool, andhas a problem in which a mechanism for performing interlocking controlof the endoscope and the treatment tool is easily enlarged andcomplicated. Additionally, this endoscopic surgery system moves thetreatment tool while following the movement of the endoscope, and doesnot move the endoscope while following the movement of the treatmenttool. For this reason, there are problems in that it is necessary to askfor an assistant's help in order to change the visual field of theendoscope, the operation for changing the observation position of theendoscope as intended by a surgeon easily becomes complicated, and thesurgery time is easily prolonged.

Additionally, since the endoscopic surgery device disclosed inJP2003-325436A has a configuration in which the endoscope and thetreatment tool are mechanically coupled and always move integrally, thevisual field of the endoscope also changes minutely in an interlockingmanner with minute movement of the treatment tool. For this reason,there is a problem in that an observation image obtained by theendoscope moves minutely and is hardly seen. Particularly when theendoscope and the treatment tool are inserted into the body cavity in aparallel state, there is a problem in which the size of an object to beobserved changes in an interlocking manner with the minute movement ofthe treatment tool, and a sense of perspective cannot be easily held.

Additionally, in a case where the endoscope and the treatment tool aremechanically interlocked with each other, a problem also occurs in thatthe interlocking between the endoscope and the treatment tool is notsmoothly performed due to a frictional force received from other members(for example, the valve member) when the endoscope or the treatment toolmoves forward and backward.

In this way, in any of the related-art techniques, there are variousproblems in order to smoothly perform the endoscopic surgery, and itcannot be said that the techniques of interlocking the endoscope and thetreatment tool inserted into the body cavity is sufficient.

The invention has been made in view of such a situation and an objectthereof is to provide an endoscopic surgical device and an overtube withwhich an endoscope and a treatment tool can be operated in aninterlocking manner as intended by a surgeon.

In order to achieve the above object, an endoscopic surgical devicerelated to a first aspect of the invention is an endoscopic surgicaldevice including an endoscope that observes the inside of a body cavity;a treatment tool that inspects or treats an affected part within thebody cavity; and an overtube that guides the endoscope and the treatmenttool into the body cavity. The overtube includes an overtube body thatpasses through a body wall and is inserted into the body cavity, anendoscope insertion passage that is provided inside the overtube bodyand allows the endoscope to be inserted therethrough so as to be movableforward and backward, a treatment tool insertion passage that isprovided inside the overtube body and allows the treatment tool to beinserted therethrough so as to be movable forward and backward, a firstvalve member that is provided in the endoscope insertion passage andsecures airtightness within the body cavity, a second valve member thatis provided in the treatment tool insertion passage and secures theairtightness within the body cavity, and an interlocking member that isconfigured to be movable forward and backward inside the overtube body,and has an endoscope-coupled part to be coupled to the endoscopeinserted through the endoscope insertion passage and a treatmenttool-coupled part to be coupled to the treatment tool inserted throughthe treatment tool insertion passage. The following formulas aresatisfied when a fixing force for fixing the interlocking member to theendoscope is defined as F1, a fixing force for fixing the interlockingmember to the treatment tool is defined as F2, and a frictional forcethat the endoscope receives from the first valve member when theendoscope moves forward and backward is defined as F3.F1>F3F2>F3

In the first aspect of the invention, it is preferable that thefollowing formula is satisfied when a frictional force that thetreatment tool receives from the second valve member when the treatmenttool moves forward and backward is defined as F4, and a fixing force forfixing the overtube to the body wall in a forward and backward movementdirection is defined as Ft.Ft>F3+F4

Additionally, in the first aspect of the invention, it is preferablethat the following formula is satisfied.F1>F2

Additionally, in the first aspect of the invention, it is preferablethat the interlocking member includes an endoscope fixed region wherethe endoscope is fixed, and a treatment tool fixed region where thetreatment tool is fixed, and the endoscope fixed region is made longerthan the treatment tool fixed region.

Additionally, in the first aspect of the invention, it is preferablethat, when a frictional force that the treatment tool receives from thesecond valve member when the treatment tool moves forward and backwardis defined as F4, either F2+F4<10 [N] or F2+F3<10 [N] is satisfied inthe case of F1>F2, and either F1+F4<10 [N] or F1+F3<10 [N] is satisfiedin the case of F1<F2 (N is Newtons).

Additionally, in the first aspect of the invention, it is preferablethat the interlocking member includes a dead zone where the forward andbackward movement of either the endoscope or the treatment tool does notinterlock with the movement of the other and a sensing zone where theforward and backward movement of either the endoscope or the treatmenttool interlocks with the movement of the other.

Additionally, in the first aspect of the invention, it is preferablethat the interlocking member includes a treatment tool-coupled membercoupled to the treatment tool, and the treatment tool-coupled member isprovided to be rotatable with respect to the interlocking member.

Additionally, in the first aspect of the invention, it is preferablethat the interlocking member includes a slider member that is coupled tothe endoscope and moves forward and backward integrally with theendoscope, and a sleeve member that is coupled to the treatment tool andmoves forward and backward integrally with the treatment tool, and arange where the sleeve member is movable forward and backward withrespect to the slider member is limited.

Additionally, in the first aspect of the invention, it is preferablethat the sleeve member is configured so as to be rotatable around theaxis with respect to the slider member.

Additionally, in the first aspect of the invention, it is preferablethat the slider member is configured so as to be non-rotatable aroundthe axis with respect to the overtube body.

Additionally, an overtube related to a second aspect of the invention isan overtube including an overtube body that passes through a body walland is inserted into a body cavity; an endoscope insertion passage thatis provided inside the overtube body and allows an endoscope forobserving the inside of the body cavity to be inserted therethrough soas to be movable forward and backward; a treatment tool insertionpassage that is provided inside the overtube body and allows a treatmenttool for inspecting or treating an affected part within the body cavityto be inserted therethrough so as to be movable forward and backward; afirst valve member that is provided in the endoscope insertion passageand secures airtightness within the body cavity; a second valve memberthat is provided in the treatment tool insertion passage and secures theairtightness within the body cavity; and an interlocking member that isconfigured to be movable forward and backward inside the overtube body,and has an endoscope-coupled part to be coupled to the endoscopeinserted through the endoscope insertion passage and a treatmenttool-coupled part to be coupled to the treatment tool inserted throughthe treatment tool insertion passage. The following formulas aresatisfied when a fixing force for fixing the interlocking member to theendoscope is defined as F1, a fixing force for fixing the interlockingmember to the treatment tool is defined as F2, and a frictional forcethat the endoscope receives from the first valve member when theendoscope moves forward and backward is defined as F3.F1>F3F2>F3Additionally, in the second aspect of the invention, it is preferablethat the following formula is satisfied when a frictional force that thetreatment tool receives from the second valve member when the treatmenttool moves forward and backward is defined as F4, and a fixing force forfixing the overtube to the body wall in a forward and backward movementdirection is defined as Ft.Ft>F3+F4

Additionally, in the second aspect of the invention, it is preferablethat the following formula is satisfied.F1>F2

Additionally, in the second aspect of the invention, it is preferablethat the interlocking member includes an endoscope fixed region wherethe endoscope is fixed, and a treatment tool fixed region where thetreatment tool is fixed, and the endoscope fixed region is made longerthan the treatment tool fixed region.

Additionally, in the second aspect of the invention, it is preferablethat, when a frictional force that the treatment tool receives from thesecond valve member when the treatment tool moves forward and backwardis defined as F4, either F2+F4<10 [N] or F2+F3<10 [N] is satisfied inthe case of F1>F2, and either F1+F4<10 [N] or F1+F3<10 [N] is satisfiedin the case of F1<F2 (N is Newtons).

Additionally, in the second aspect of the invention, it is preferablethat the interlocking member includes a dead zone where the forward andbackward movement of either the endoscope or the treatment tool does notinterlock with the movement of the other and a sensing zone where theforward and backward movement of either the endoscope or the treatmenttool interlocks with the movement of the other.

According to the invention, the frictional force (F3) between the valvemember (first valve member) for securing the airtightness within thebody cavity and the endoscope, is smaller than any of the fixing force(F1) for fixing the interlocking member to the endoscope and the fixingforce (F2) for fixing the interlocking member to the treatment tool.Thus, when the treatment tool is operated to move forward and backwardwith respect to the interlocking member, the coupling position of thetreatment tool or the endoscope with the interlocking member does notshift due to the frictional force of the valve member. Therefore, it ispossible operate the endoscope and the treatment tool in an interlockingmanner as intended by the surgeon without causing the malfunction of theendoscope due to the friction with the valve member.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic configuration diagram of an endoscopic surgicaldevice related to the invention.

FIG. 2 is a plan view illustrating a distal end surface of an endoscopeinsertion part.

FIG. 3 is an external appearance perspective view illustrating anovertube from the rear upper left.

FIG. 4 is a sectional view, as seen from arrow 4-4 of FIG. 3,illustrating the internal structure of the overtube.

FIG. 5 is a sectional view of the periphery of a base end cap cut in aplane orthogonal to a paper surface of FIG. 4.

FIG. 6 is an enlarged sectional view illustrating a portion of FIG. 4 inan enlarged manner.

FIG. 7 is a sectional view as seen from arrow 7-7 in FIG. 6.

FIG. 8 is a perspective view illustrating a slider from the rear upperleft.

FIG. 9 is a perspective view illustrating the slider from the rear upperright.

FIG. 10 is a sectional view of the slider.

FIG. 11 is an explanatory view used for the description of the action ofthe slider.

FIG. 12 is an explanatory view used for the description of the action ofthe slider.

FIG. 13 is an explanatory view used for the description of the action ofthe slider.

FIG. 14 is an explanatory view used for the description of the action ofthe slider.

FIG. 15 is a sectional view illustrating another embodiment of thesupporting mechanism of the slider in the overtube.

FIG. 16 is a sectional view illustrating another embodiment of thesupporting mechanism of the slider in the overtube.

FIG. 17 is a perspective view illustrating a state where an inner needlehas been mounted on the overtube, from the front upper left.

FIG. 18 is a perspective view illustrating a state where the innerneedle has been mounted on the overtube, from the rear lower left.

FIG. 19 is a perspective view illustrating the inner needle from thefront lower left.

FIG. 20 is a perspective view illustrating a situation in which theinner needle is mounted on the overtube.

FIGS. 21A to 21C are views illustrating a situation in which theovertube is inserted into a body wall.

FIGS. 22A and 22B are views illustrating a situation in which thetreatment tool insertion part is pushed into the affected part sidewithin the body cavity from the hand side.

FIGS. 23A and 23B are views illustrating a situation in which thetreatment tool insertion part is pushed into the affected part sidewithin the body cavity from the hand side.

FIGS. 24A and 24B are views illustrating a situation in which thetreatment tool insertion part is pulled to the hand side from theaffected part side within the body cavity.

FIGS. 25A and 25B are views illustrating a situation in which thetreatment tool insertion part is pulled to the hand side from theaffected part side within the body cavity.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A preferred embodiment of the invention will be described below indetail according to the accompanying drawings. In addition, any drawingmay illustrate main parts in an exaggerated manner for description, andmay have dimensions different from actual dimensions.

<Configuration of Endoscopic Surgical Device>

FIG. 1 is a schematic configuration diagram of an endoscopic surgicaldevice related to the invention. As illustrated in FIG. 1, an endoscopicsurgical device 10 includes an endoscope 100 that observes the inside ofa patient's body cavity, a treatment tool 200 for inspecting or treatingan affected part within the patient's body cavity, and an overtube 300(guide member) that guides the endoscope 100 and the treatment tool 200into the body cavity.

<Configuration of Endoscope>

The endoscope 100 includes an elongated insertion part (hereinafterreferred to as “endoscope insertion part”) 102 that is, for example, ahard endoscope, such as a laparoscope, and that is inserted into a bodycavity, and an operating part 104 that is provided continuously with abase end side of the endoscope insertion part 102. A universal cable 106is connected to the operating part 104, and each of a processor device108 and a light source device 110 is detachably connected to a distalend part of the universal cable 106 via a connector (not illustrated).Additionally, the processor device 108 is connected to a monitor 112 viaa cable.

As illustrated in FIG. 2, a distal end surface 114 of the endoscopeinsertion part 102 is provided with an observation window 116 andillumination windows 118 and 118.

An objective lens of an observation optical system, and image pick-upelements, such as a charge-coupled device (CCD) and a complementarymetal-oxide semiconductor (CMOS), which are arranged at an image pick-upposition of the objective lens, are disposed behind the observationwindow 116. A signal cable (not illustrated) is connected to a substratethat supports the image pick-up element. The signal cable is insertedthrough the endoscope insertion part 102, the operating part 104, andthe universal cable 106, and the like of FIG. 1, is provided to extendup to the connector (not illustrated), and is connected to the processordevice 108. An observation image picked up by the observation window 116is formed on a light-receiving surface of the image pick-up element, andis converted into electrical signals (image pick-up signals), and theelectrical signals are output to the processor device 108 via the signalcable and are converted into video signals. Then, the video signals areoutput to the monitor 112 connected to the processor device 108, and theobservation image (endoscope image) is displayed on a screen of themonitor 112.

An exit end of a light guide (not illustrated) is disposed behind theillumination windows 118 and 118 of FIG. 2. The light guide is insertedthrough the endoscope insertion part 102, the operating part 104, andthe universal cable 106 of FIG. 1 and has an incident end disposedwithin the connector (not illustrated). Therefore, by coupling theconnector to the light source device 110, the illumination lightradiated from the light source device 110 is transmitted to theillumination windows 118 and 118 via the light guide, and is radiatedforward from the illumination windows 118 and 118. In addition, in FIG.2, the two illumination windows 118 and 118 are disposed on the distalend surface 114 of the endoscope insertion part 102. However, the numberof the illumination windows 118 is not limited, and the number thereofmay be one or three or more.

<Configuration of Treatment Tool>

As illustrated in FIG. 1, the treatment tool 200 consists of, forexample, forceps, and includes an elongated insertion part (hereinafterreferred to as a “treatment tool insertion part”) 202 that is insertedinto a body cavity, an operating part 204 that is provided on the baseend side of the treatment tool insertion part 202 and is gripped by asurgeon, and a treatment part 206 that is provided on a distal end sideof the treatment tool insertion part 202 and is operable by theoperation of the operating part 204.

The treatment tool insertion part 202 is provided with a tubular sheath208, and an operating shaft (not illustrated) that is inserted into thesheath 208 so as to be movable in the direction of an axial center.Moreover, the operating part 204 is provided with a fixed handle 210,and a movable handle 214 that is rotatably coupled to the fixed handle210 via a turning pin. A base end part of the operating shaft is coupledto the movable handle 214.

The treatment part 206 is provided with a pair of gripping memberscapable of being openable and closable. The gripping members are coupledto a distal end part of the operating shaft via a driving mechanism (notillustrated). With the rotational operation of the movable handle 214 ofthe operating part 204, the gripping members of the treatment part 206are opened and closed via the operating shaft and the driving mechanism.

In addition, the treatment tool 200 is not limited to the forceps, andmay be, for example, other treatment tools, such as a laser probe, asuture device, an electric scalpel, a needle holder, and an ultrasonicaspirator.

<Configuration of Overtube>

FIG. 3 is an external appearance perspective view illustrating theovertube 300 from the rear upper left.

As illustrated in this drawing, the overtube 300 has an endoscopeinsertion passage 306 through which the endoscope insertion part 102 ofthe endoscope 100 is inserted so as to be movable forward and backward,and a treatment tool insertion passage 308 through which the treatmenttool insertion part 202 of the treatment tool 200 is inserted so as tobe movable forward and backward.

The endoscope insertion passage 306 has a diameter such that at leastthe endoscope insertion part 102 is capable of being insertedtherethrough, using an endoscope insertion axis 306 a, which is parallelto a reference axis 300 a (longitudinal axis) indicating a central axisof the entire overtube 300, as a central axis, and indicates a spaceportion within the overtube 300 that penetrates from a base end surface302 of the overtube 300 to a distal end surface 304 thereof. Theendoscope insertion axis 306 a is equivalent to the position of the axis(central axis) of the endoscope insertion part 102 that is insertedthrough the endoscope insertion passage 306.

The base end surface 302 is provided with an endoscope insertion opening310 for allowing the endoscope insertion part 102 to be inserted intothe endoscope insertion passage 306 therethrough, and the distal endsurface 304 is provided with an endoscope delivery opening 312 forallowing the endoscope insertion part 102 inserted into the endoscopeinsertion passage 306 to be delivered to the outside therethrough.

The treatment tool insertion passage 308 has a diameter such that atleast the treatment tool insertion part 202 is capable of being insertedtherethrough, using a treatment tool insertion axis 308 a parallel tothe reference axis 300 a as a central axis, and indicates a spaceportion within the overtube 300 that penetrates from the base endsurface 302 of the overtube 300 to the distal end surface 304. Thetreatment tool insertion axis 308 a is equivalent to the position of theaxis (central axis) of the treatment tool insertion part 202 that isinserted through the treatment tool insertion passage 308.

The base end surface 302 is provided with a treatment tool insertionopening 314 for allowing the treatment tool insertion part 202 to beinserted into the treatment tool insertion passage 308 therethrough, andthe distal end surface 304 is provided with a treatment tool deliveryopening 316 for allowing the treatment tool insertion part 202 insertedinto the treatment tool insertion passage 308 to be delivered to theoutside therethrough.

Additionally, the overtube 300 has an air supply connector 318(fluid-supplying connector) on the base end surface 302. The air supplyconnector 318 is provided at the end part of an air supply pipe linethat communicates with the endoscope insertion passage 306 and thetreatment tool insertion passage 308 inside the overtube 300.

One end part of an air supply tube 122 (tube member) illustrated in FIG.1 is connected to the air supply connector 318, and the other end partof the air supply tube 122 is connected to a pneumoperitoneum device120. Therefore, if pneumoperitoneum gas (gas for pneumoperitoneum), suchas carbon dioxide gas, is supplied from the pneumoperitoneum device 120to the air supply tube 122, the pneumoperitoneum gas is sent from theair supply connector 318 to the inside of the overtube 300, and isdelivered from the endoscope delivery opening 312 and the treatment tooldelivery opening 316 of the distal end surface 304 through the inside ofthe overtube 300 to the outside of the overtube 300.

In addition, regarding the position and orientation of a space where theovertube 300 has been arranged, terms called front, rear, left, right,up, and down are used with the orientation from the base end surface 302in a direction along the reference axis 300 a to the distal end surface304 defined as the front and with the orientation from the referenceaxis 300 a to the endoscope insertion axis 306 a defined as the left.

(Internal Structure of Overtube)

The specific configuration of the overtube 300 will be described. FIG. 4is a sectional view (a sectional view as seen arrow 4-4 of FIG. 3)illustrating the internal structure of the overtube 300, and illustratesa section cut in a plane that includes the reference axis 300 a andorthogonal to an upward-downward direction. In the presentspecification, when a drawing is simply called a sectional view, thedrawing illustrates a sectional view cut by the same plane as FIG. 4.

As illustrated in this drawing, the overtube 300 has an overtube body320 that occupies substantially the entire area in a forward-rearwarddirection, a base end cap 340 that is arranged at a rear part of theovertube 300, a distal end cap 360 that is arranged at a distal endpart, and a slider 400 (interlocking member) that is arranged inside theovertube 300. In addition, the base end cap 340 and the distal end cap360 are some of the constituent elements of the overtube body of theinvention, and may be formed separately from or formed integrally withthe overtube body 320.

(Description of Overtube Body)

The overtube body 320 is formed in an elongated cylindrical shape havingthe reference axis 300 a as a central axis using hard resin, metal, orthe like, and has an outer wall 322 that surrounds an outer periphery,and a lumen 324 that penetrates from a base end of the overtube body 320to a distal end thereof.

The lumen 324 has the endoscope insertion axis 306 a and the treatmenttool insertion axis 308 a inserted therethrough, and is provided with aspace that serves as the endoscope insertion passage 306 and thetreatment tool insertion passage 308.

Additionally, the lumen 324 serves as the air supply pipe line throughwhich the pneumoperitoneum gas sent in from the air supply connector 318passes.

The base end cap 340 is attached to the base end of the overtube body320, and is formed in a columnar shape made to have a larger diameterthan the external diameter of the overtube body 320, using hard resin,metal, or the like. The base end cap 340 has a flat rear end surfaceserving as the base end surface 302 of the overtube 300 on the rear sidethereof, and has through-holes 342 and 344 that penetrate from the baseend surface 302 to the lumen 324 of the overtube body 320.

The through-hole 342 has a central axis arranged coaxially with theendoscope insertion axis 306 a, and forms a portion of the endoscopeinsertion passage 306. An opening of the through-hole 342 in the baseend surface 302 is equivalent to the above-described endoscope insertionopening 310.

The through-hole 344 has a central axis arranged coaxially with thetreatment tool insertion axis 308 a, and forms a portion of thetreatment tool insertion passage 308. An opening of the through-hole 344in the base end surface 302 is equivalent to the above-describedtreatment tool insertion opening 314.

Valve members 346 and 348 (a first valve member 346, a second valvemember 348) are respectively arranged in the through-hole 342 and thethrough-hole 344. Although the detailed description of the valve members346 and 348 is omitted, the valve members have, for example, slits thatopen only when being inserted through the endoscope insertion part 102and the treatment tool insertion part 202 and that come into closecontact with outer peripheral surfaces (side surfaces) of the endoscopeinsertion part 102 and the treatment tool insertion part 202 without asubstantial gap. This secures the airtightness of spaces closer to thedistal end side than the valve members 346 and 348, and reduces theleakage or the like of the pneumoperitoneum gas injected into the bodycavity to the outside of the body.

In addition, the valve members 346 and 348 are not limited to those withthe specific configuration, and valve members with widely-knownarbitrary configurations can be used. Although FIG. 4 illustrates aconfiguration in which the two valve members are respectively arrangedin the through-hole 342 and the through-hole 344, a configuration inwhich one valve member or three or more valve members are arranged maybe adopted.

(Description of Air Supply Connector)

Additionally, FIG. 5 is a sectional view of the periphery of the baseend cap 340 when the overtube 300 is cut in a plane that includes thereference axis 300 a and is orthogonal to the paper surface of FIG. 4.As illustrated in this drawing, the base end cap 340 has a through-hole350 that penetrates from the base end surface 302 to the lumen 324 ofthe overtube body 320.

The through-hole 350 is a portion of the air supply pipe line thatallows the pneumoperitoneum gas to flow therethrough, and has a rear endpart formed at a position below the reference axis 300 a. The rear endpart is provided with the above-described air supply connector 318 towhich the air supply tube 122 (refer to FIG. 1) from thepneumoperitoneum device 120 is connected.

The air supply connector 318 is formed in an elongated cylindricalshape, and has a part buried and fixed inside the through-hole 350.Accordingly, at a position below the reference axis 300 a in the baseend surface 302, the axis (central axis) of the air supply connector 318is arranged so as to be substantially orthogonal to the base end surface302 (arranged parallel to the reference axis 300 a), and the air supplyconnector 318 is provided to protrude rearward from the base end surface302.

The air supply tube 122 is connected to the air supply connector 318 byfitting the air supply tube 122 to the outer periphery of the air supplyconnector 318. Then, if the pneumoperitoneum gas is delivered from thepneumoperitoneum device 120 to the air supply tube 122, thepneumoperitoneum gas is sent into the lumen 324 of the overtube body 320from the air supply connector 318.

(Merits Based on Arrangement of Air Supply Connector on Base EndSurface)

Here, in an overtube that guides one medical instrument into a bodycavity, it is general that the air supply connector is provided not on abase end surface of the overtube but on a side surface thereof.

This is because the air supply connector may interfere with an innerneedle supposing that the air supply connector is provided on the baseend surface, and because the overtube can be rotated around the axis soas to prevent the interference of the air supply connector and the airsupply tube with a body wall without influencing the position of themedical instrument inserted through the overtube even if the air supplyconnector is provided on the side surface.

On the other hand, in the overtube 300 of the present embodiment, if theovertube 300 is rotated around the axis, the position of the endoscopeinsertion part 102 and the treatment tool insertion part 202 changes.Therefore, a case where it is difficult to avoid any interference of theair supply connector 318 and the air supply tube 122 with the body wallwhile maintaining the positions of the endoscope insertion part 102 andthe treatment tool insertion part 202 within the body cavity atpositions desired by a surgeon may occur.

Thus, in the overtube 300 of the present embodiment, the interference ofthe air supply connector 318 and the air supply tube 122 with the bodywall is prevented by arranging the air supply connector 318 on the baseend surface 302 of the overtube 300, and the interference of the airsupply tube with the inner needle is avoided by devising theconfiguration of the inner needle as will be described below.

In addition, the air supply pipe line within the air supply connector318 and the overtube 300 may be provided in order to supply fluids otherthan the pneumoperitoneum gas into a body cavity.

The distal end cap 360 illustrated in FIG. 4 is attached to the distalend of the overtube body 320, and is formed of hard resin, metal, or thelike. The distal end cap 360 has a front surface serving as the distalend surface 304 of the overtube 300 on a front side thereof, and hasthrough-holes 362 and 364 that penetrate from the lumen 324 of theovertube body 320 to the distal end surface 304.

The through-hole 362 has a central axis arranged coaxially with theendoscope insertion axis 306 a, and forms a portion of the endoscopeinsertion passage 306. An opening of the through-hole 362 in the distalend surface 304 is equivalent to the above-described endoscope deliveryopening 312.

The through-hole 364 has a central axis arranged coaxially with thetreatment tool insertion axis 308 a, and forms a portion of thetreatment tool insertion passage 308. An opening of the through-hole 364in the distal end surface 304 is equivalent to the above-describedtreatment tool delivery opening 316.

Additionally, as described above, the pneumoperitoneum gas sent into thelumen 324 of the overtube body 320 via the air supply tube 122, the airsupply connector 318 of the base end cap 340, and the through-hole 350from the pneumoperitoneum device 120 is delivered to the outside (theinside of a body cavity) via the through-hole 362 and the through-hole364.

Although the overtube body 320, the base end cap 340, and the distal endcap 360 above form the outer wall of the overtube 300, the outer wall ofthe overtube 300 may not necessarily be constituted of these separatedmembers.

The air supply pipe line of the overtube body 320 through which thepneumoperitoneum gas passes may be a lumen that is provided separatelyfrom the lumen 324.

(Description of Slider)

Next, the slider 400 will be described.

The slider 400 illustrated in FIG. 4 is housed within the lumen 324 ofthe overtube body 320, and is supported so as to be movable forward andbackward in the direction of the reference axis 300 a.

The slider 400 is an interlocking member that is coupled to theendoscope insertion part 102 inserted through the endoscope insertionpassage 306 and the treatment tool insertion part 202 inserted throughthe treatment tool insertion passage 308 and that has a dead zone wherethe forward and backward movement of either the endoscope insertion partor the treatment tool insertion part in the forward-rearward direction(axial direction) does not interlock with the movement of the other anda sensing zone where the forward and backward movement of either theendoscope insertion part or the treatment tool insertion part interlockswith the movement of the other.

That is, the endoscope insertion part 102 is adapted to interlock withthe forward and backward movement of the treatment tool insertion part202 in the axial direction with play.

Accordingly, when a surgeon has moved the treatment tool insertion part202 forward and backward in the axial direction and when the axialdisplacement of the treatment tool insertion part 202 is large (when aforward and backward movement of a large amplitude has been performed),the endoscope insertion part 102 also moves in an interlocking mannerforward, backward, upward, downward, rightward, and leftward. Thus, thevisual field, orientation, and the like of the endoscope 100 can bechanged as intended by a surgeon. Additionally, the visual field isalways given to pick up an image of a treatment tool distal end, andconsequently, an image that is optimal for treatment is automaticallyprovided. When it is desired to check places other than the treatmentpart, the checking can be performed by moving forceps, and a surgeon canperform operations as desired. Therefore, an assistant (scopist) whooperates the endoscope 100 apart from the surgeon can be madeunnecessary, and a troublesome condition in which the surgeon shouldinstruct an assistant about the visual field, orientation, and the likeof the endoscope serially can be eliminated.

Additionally, when the axial displacement of the treatment toolinsertion part 202 is small (when a forward and backward movement of asmall amplitude has been performed), the endoscope insertion part 102does not interlock. Therefore, the size of an object to be observedwithin an observation image can be prevented from fluctuatingunnecessarily, a sense of perspective can be suitably maintained, and astable observation image can be provided.

(Internal Structure of Slider)

The internal structure of the slider 400 will be described.

FIG. 6 is an enlarged sectional view illustrating a portion, in whichthe slider 400 is arranged in FIG. 4, in an enlarged manner, andillustrates a state where the endoscope insertion part 102 and thetreatment tool insertion part 202 have been inserted through theendoscope insertion passage 306 and the treatment tool insertion passage308, respectively.

FIG. 7 is a view as seen from arrow 7-7 in FIG. 6.

Additionally, FIGS. 8 and 9 are respectively perspective viewsillustrating the slider 400 from the rear upper left and from the rearupper right and FIG. 10 is a sectional view of only the slider 400.

As illustrated in FIGS. 6 to 10, the slider 400 has a slider body 402(slider member) that holds components of the slider 400. The slider body402, as illustrated in FIGS. 7 to 9, has a flat upper surface 404 and aflat lower surface 406, and has protruding strips 408 and 410,respectively, on the upper surface 404 and the lower surface 406.

The protruding strips 408 and 410 respectively protrude in theupward-downward direction at substantially central parts of the uppersurface 404 and the lower surface 406 in a leftward-rightward direction,extend in the direction (forward-rearward direction) of the referenceaxis 300 a within the lumen 324 of the overtube body 320, and are fittedinto guide grooves 370 and 372 provided in an upper part and a lowerpart within the lumen 324 of the overtube body 320 as illustrated inFIG. 7.

The guide grooves 370 and 372 are respectively formed by gaps between apair of left and right guide plates 374 and 374 and a pair of left andright the guide plates 376 and 376 that are arranged at the upper partand the lower part within the lumen 324.

The guide plates 376 and 376 arranged at the lower part within the lumen324 are illustrated in FIG. 4. As illustrated in this drawing, the guideplates 374 and 374 and the guide plates 376 and 376 are respectivelyformed in the shape of a long plate, and are installed along thedirection of the reference axis 300 a by being laid between the base endcap 340 and the distal end cap 360.

Accordingly, the guide grooves 370 and 372 are respectively arrangedalong the direction of the reference axis 300 a from the base end cap340 to the distal end cap 360 within the lumen 324.

As illustrated in FIG. 7, in a state where the slider 400 is housed andarranged within the lumen 324, the protruding strips 408 and 410 arerespectively fitted into the guide grooves 370 and 372, and the uppersurface 404 and the lower surface 406 respectively contact or approachthe guide plates 374 and 374 and the guide plates 376 and 376.Accordingly, the slider 400 (slider body 402) is supported so as to bemovable forward and backward in the forward-rearward direction withinthe lumen 324, and is supported in a state where the movement of theslider in the upward-downward direction and in the leftward-rightwarddirection and the rotation of the slider in all directions arerestricted (a state where the rotation of the slider around at least thereference axis 300 a is impossible).

In addition, the guide grooves 370 and 372 may not be formed by theguide plates 374 and 374 and the guide plates 376 and 376 arrangedwithin the lumen 324 of the overtube body 320, and may be formed in theouter wall 322 of the overtube body 320 or may be formed by otherconfigurations.

Additionally, a range (movable range) in which the slider 400 (sliderbody 402) moves forward and backward in the forward-rearward directionwith respect to the overtube body 320 is a range having a position wherethe slider 400 abuts against the base end cap 340 as a rear end (aposition closest to the base end) and having a position where the sliderabuts against the distal end cap 360 as a front end (a position closestto the distal end). However, the rear end and the front end of themovable range of the slider 400 may not be restricted by the base endcap 340 and the distal end cap 360.

Additionally, the slider 400, as illustrated in FIG. 10, has aendoscope-coupled part 420 that is coupled (engaged) with the endoscopeinsertion part 102, and a treatment tool-coupled part 422 that iscoupled (engaged) with the treatment tool insertion part 202.

(Description of Endoscope-Coupled Part)

The endoscope-coupled part 420 is provided on the left side of theslider body 402, and includes a through-hole 424 in which a spaceserving as the endoscope insertion passage 306 is secured within thelumen 324 of the overtube body 320 and through which, as illustrated inFIG. 6, the endoscope insertion part 102 is inserted, and apressure-contact member 426 that is brought into pressure contact withthe outer peripheral surface (side surface) of the endoscope insertionpart 102 inserted through the endoscope insertion passage 306.

The through-hole 424 is formed to penetrate from a rear end of theslider body 402 to a front end thereof, and has a larger diameter thanthe external diameter of at least the endoscope insertion part 102. Acentral axis of the through-hole 424 is arranged coaxially with theendoscope insertion axis 306 a within the lumen 324.

A pressure-contact member attachment part 428 for attaching thepressure-contact member 426 is provided on the rear end side of thethrough-hole 424.

The pressure-contact member attachment part 428 has an internal diameterthat is made larger than other position ranges of the through-hole 424,and has formed therein an opening 430 (refer to FIG. 8) that penetratesup to an outer surface (left side surface 431) of the slider body 402 ina partial range thereof (a left side surface of the slider 400) in thecircumferential direction. The pressure-contact member 426 is fittedinto the through-hole 424 from the opening 430, and the pressure-contactmember 426 is fixed to the slider body 402 in the pressure-contactmember attachment part 428.

The pressure-contact member 426, as illustrated in FIG. 7, is annularlyformed of an elastic material, such as elastic rubber or a spring, and acentral axis of a through-hole 432 thereof is arranged coaxially withthe endoscope insertion axis 306 a.

Accordingly, when the endoscope insertion part 102 is inserted throughthe endoscope insertion passage 306, as illustrated in FIG. 6, theendoscope insertion part 102 is inserted through the through-hole 432 ofthe pressure-contact member 426.

In addition, the position of an outer peripheral surface of thepressure-contact member 426 in the opening 430 of the pressure-contactmember attachment part 428 substantially coincides with the position ofthe left side surface 431 of the slider body 402 around the opening 430.That is, the opening 430 of the pressure-contact member attachment part428 provides a space for arranging the pressure-contact member 426, andas compared to a configuration in which the pressure-contact member 426is completely housed inside the slider body 402, the slider body 402 isminiaturized, and the external diameter of the overtube body 320 is alsomade smaller along with this miniaturization. However, a configurationin which the pressure-contact member 426 is completely housed inside theslider body 402 may be adopted.

Additionally, the internal diameter (the diameter of the through-hole432) of the pressure-contact member 426 is slightly smaller than theexternal diameter of the endoscope insertion part 102.

Therefore, when the endoscope insertion part 102 is inserted through thethrough-hole 432 of the pressure-contact member 426, the through-hole432 is pushed and widened and the pressure-contact member 426 isdeformed. An elastic force is generated in the pressure-contact member426 due to this deformation, and the pressure-contact member 426 isbrought into pressure contact (engaged) with the endoscope insertionpart 102 inserted through the through-hole 432.

Therefore, a frictional force acts on the relative movement between theendoscope insertion part 102 and the pressure-contact member 426. Then,unless a larger external force than the frictional force is appliedbetween the endoscope insertion part 102 and the pressure-contact member426, the relative movement does not occur between the endoscopeinsertion part 102 and the pressure-contact member 426, and theendoscope insertion part 102 and the slider 400 (slider body 402) arebrought into a state where they are coupled (engaged) in aninterlockable manner via the pressure-contact member 426.

Accordingly, the slider 400 (slider body 402) also integrally movesforward and backward in an interlocking manner with the forward andbackward movement of the endoscope insertion part 102 in theforward-rearward direction (axial direction).

In addition, since the coupling here is based on the elastic force ofthe pressure-contact member 426, the engagement position (a positionwhere the slider 400 is engaged in the endoscope insertion part 102) ofthe endoscope insertion part 102 coupled to the slider 400 (slider body402) can be arbitrarily adjusted.

(Description of Treatment Tool-Coupled Part)

The treatment tool-coupled part 422, as illustrated in FIG. 10 isprovided on the right side of the slider body 402, and includes a sleeve440 (sleeve member) that is coupled to the treatment tool insertion part202, and a guide part 460 that guides the sleeve 440 so as to be movableforward and backward in the direction (forward-rearward direction) ofthe treatment tool insertion axis 308 a.

The sleeve 440 is housed in a sleeve housing space 464 of the guide part460 to be described below in detail, is supported so as to be movableforward and backward in the forward-rearward direction, and asillustrated in FIG. 7, includes a sleeve body (frame body) 444 thatsurrounds the outside of the sleeve, and a pressure-contact member 446that is arranged inside the sleeve.

The sleeve body 444 is formed in a cylindrical shape, and has athrough-hole 448 with a larger diameter than the external diameter of atleast the treatment tool insertion part 202. The central axis of thethrough-hole 448 is arranged coaxially with the treatment tool insertionaxis 308 a within the lumen 324 of the overtube body 320, and secures aspace for the treatment tool insertion passage 308.

The pressure-contact member 446 is annularly formed of an elasticmaterial, such as elastic rubber or a spring, and is fitted into thethrough-hole 448 of the sleeve body 444 and fixed to the sleeve body444. A central axis of a through-hole 450 of the pressure-contact member446 is arranged coaxially with the treatment tool insertion axis 308 awithin the lumen 324 of the overtube body 320.

Therefore, when the treatment tool insertion part 202 is insertedthrough the treatment tool insertion passage 308, as illustrated in FIG.6, the treatment tool insertion part 202 is inserted through thethrough-hole 450 of the pressure-contact member 446.

Additionally, the internal diameter (the diameter of the through-hole450) of the pressure-contact member 446 is slightly smaller than theexternal diameter of the treatment tool insertion part 202.

Therefore, when the treatment tool insertion part 202 is insertedthrough the through-hole 450 of the pressure-contact member 446, thethrough-hole 450 is pushed and widened and the pressure-contact member446 is deformed. An elastic force is generated in the pressure-contactmember 446 due to this deformation, and the pressure-contact member 446is brought into pressure contact (engaged) with the treatment toolinsertion part 202 inserted through the through-hole 450.

Therefore, a frictional force acts on the relative movement between thetreatment tool insertion part 202 and the pressure-contact member 446.Then, unless a larger external force than the frictional force isapplied between the treatment tool insertion part 202 and thepressure-contact member 446, the relative movement does not occurbetween the treatment tool insertion part 202 and the pressure-contactmember 446, and the treatment tool insertion part 202 and the sleeve 440are brought into a state where they are coupled (engaged) in aninterlockable manner via the pressure-contact member 446.

Accordingly, the sleeve 440 also integrally moves forward and backwardin an interlocking manner with the forward and backward movement of thetreatment tool insertion part 202 in the forward-rearward direction(axial direction).

Additionally, the sleeve 440 also rotates with respect to the sliderbody 402 in an interlocking manner with the rotation around the axis ofthe treatment tool insertion part 202.

In addition, since the coupling between the treatment tool insertionpart 202 and the sleeve 440 herein is based on the elastic force of thepressure-contact member 446, the engagement position (a position wherethe sleeve 440 is engaged in the treatment tool insertion part 202) ofthe treatment tool insertion part 202 coupled to the sleeve 440 can bearbitrarily adjusted.

Additionally, a region where the endoscope insertion part 102 is fixedto the endoscope-coupled part 420 of the slider 400 is referred to as anendoscope fixed region, and a region where the treatment tool insertionpart 202 is fixed to the treatment tool-coupled part 422 of the slider400 is referred to as a treatment tool fixed region. In the presentform, the endoscope fixed region is equivalent to a region of an innerperipheral surface of the pressure-contact member 426 that is broughtinto pressure contact with the outer peripheral surface of the endoscopeinsertion part 102, and the treatment tool fixed region is equivalent toa region of an inner peripheral surface of the pressure-contact member446 that is brought into pressure contact with the outer peripheralsurface of the treatment tool insertion part 202. In this case, it isdesirable that the endoscope fixed region is configured so as to becomelonger in the axial direction than the treatment tool fixed region.

Meanwhile, the guide part 460 of the treatment tool-coupled part 422, asillustrated in FIGS. 7 and 9, has a guide surface 462 that extends inthe direction of the treatment tool insertion axis 308 a (reference axis300 a) within the lumen 324 of the overtube body 320.

The guide surface 462 is curved in a U-shape toward an opening in asection orthogonal to the reference axis 300 a, and as illustrated inFIG. 7, an inner peripheral surface of the overtube body 320 (outer wall322) is arranged so as to face the opening of the guide surface 462,within the lumen 324 of the overtube body 320.

Accordingly, a space surrounded by the guide surface 462 and the innerperipheral surface of the overtube body 320 is formed as the sleevehousing space 464 of the guide part 460.

The sleeve housing space 464 is formed at a position where the treatmenttool insertion axis 308 a is inserted therethrough, and extends alongthe treatment tool insertion axis 308 a.

The sleeve 440 is housed and arranged in the sleeve housing space 464 asdescribed above, and a central axis of the sleeve 440 is arrangedcoaxially with the treatment tool insertion axis 308 a.

In the sleeve housing space 464, an outer peripheral surface of thesleeve 440 comes in contact with or approaches the guide surface 462 andthe inner peripheral surface of the overtube body 320.

Accordingly, in the sleeve housing space 464, the sleeve 440 issupported so as to be movable in the forward-rearward direction androtatable around the axis, and is supported in a state where themovement of the sleeve in the upward-downward direction and in theleftward-rightward direction is restricted.

Additionally, the guide part 460 (slider body 402), as illustrated inFIGS. 9 and 10, has end edge parts 466 and 468, which are formed toprotrude in a direction orthogonal to the guide surface 462 along an endedge of the guide surface 462, respectively, on the base end side andthe distal end side thereof.

The end edge parts 466 and 468 abut against the end part of the sleeve440 to restrict the movement of the sleeve 440, when the sleeve 440arranged in the sleeve housing space 464 moves forward and backward inthe forward-rearward direction.

Therefore, a range (movable range) where the sleeve 440 moves forwardand backward in the forward-rearward direction with respect to theslider body 402 is limited with a position where the sleeve abutsagainst the end edge part 466 being defined as a rear end and a positionwhere the sleeve abuts against the end edge part 468 being defined as afront end. However, the rear end and the front end of the movable rangeof the sleeve 440 may not be restricted by the end edge part 466 and theend edge part 468.

In addition, in the present embodiment, the sleeve housing space 464 ofthe guide part 460 is formed by the guide surface 462 of the slider body402 and the inner peripheral surface of the overtube body 320.Therefore, as compared to a configuration in which the sleeve housingspace 464 is formed only by the slider body 402 and the sleeve 440 iscompletely housed inside the slider body 402, the slider body 402 isminiaturized, and the external diameter of the overtube body 320 is alsomade smaller along with this miniaturization. However, a configurationin which the sleeve 440 is completely housed inside the slider body 402may be adopted.

(Action of Slider when Endoscope and Treatment Tool are Coupled)

According to the slider 400 configured as described above, the endoscopeinsertion part 102 inserted through the endoscope insertion passage 306of the overtube 300 and the slider body 402 are coupled, and thetreatment tool insertion part 202 inserted through the treatment toolinsertion passage 308 of the overtube 300 and the sleeve 440 arecoupled.

As illustrated in FIG. 11, it is supposed that a surgeon performs aforward and backward movement for moving the treatment tool insertionpart 202 forward and backward in the axial direction (forward-rearwarddirection) in a state where the sleeve 440 has not reached the rear endand the front end of the movable range thereof with respect to theslider body 402.

In this case, when the sleeve 440 has moved forward and backward withinthe movable range thereof with respect to the slider body 402, theslider body 402 does not move with respect to the forward and backwardmovement of the treatment tool insertion part 202. Therefore, the deadzone where the endoscope insertion part 102 does not interlock with theforward and backward movement of the treatment tool insertion part 202is present.

On the other hand, as illustrated in FIG. 12, if the treatment toolinsertion part 202 is moved backward in a state where the sleeve 440reaches the rear end of the movable range thereof with respect to theslider body 402, the sleeve 440 and the slider body 402 move backwardwith respect to the overtube body 320 together with the treatment toolinsertion part 202. Accordingly, the endoscope insertion part 102 movesbackward in an interlocking manner with the treatment tool insertionpart 202.

Similarly, as illustrated in FIG. 13, if the treatment tool insertionpart 202 is moved forward in a state where the sleeve 440 reaches thefront end of the movable range thereof with respect to the slider body402, the sleeve 440 and the slider body 402 move forward with respect tothe overtube body 320 together with the treatment tool insertion part202. Accordingly, the endoscope insertion part 102 moves forward in aninterlocking manner with the treatment tool insertion part 202.

Therefore, when the treatment tool insertion part 202 has been largelydisplaced in the axial direction as described above (when the forwardand backward movement of a large amplitude has been performed), theendoscope insertion part 102 is displaced in the axial direction in aninterlocking manner with the treatment tool insertion part 202, and whenthe displacement of the treatment tool insertion part 202 in the axialdirection is small (when the forward and backward movement of a smallamplitude is performed), the endoscope insertion part 102 is notdisplaced in the axial direction.

Additionally, in the present embodiment, the slider body 402 isrestricted only in forward and backward movement in the forward-rearwarddirection, whereas the sleeve 440 is supported so as to be rotatablearound the axis with respect to the slider body 402. Therefore, asillustrated in FIG. 14, when the treatment tool insertion part 202 isoperated to rotate around the axis, the slider body 402 does not rotate,and the treatment tool insertion part 202 and the sleeve 440 rotatearound the axis.

Therefore, the rotational angle of the treatment tool insertion part 202around the axis can be changed, without changing the positions of theendoscope insertion part 102 and the treatment tool insertion part 202(the positions thereof within a body cavity) with respect to theovertube 300.

That is, when a treatment is performed on a predetermined affected partby inserting the endoscope insertion part 102 and the treatment toolinsertion part 202 through the overtube 300 inserted into a body wall,in a general procedure, the endoscope 100 is used such that the positionof the endoscope insertion part 102 in the upward-downward direction andin the leftward-rightward direction and the rotational angle thereofaround the axis are fixed.

Meanwhile, the rotational operation of the treatment tool insertion part202 around the axis is appropriately performed similar to the forwardand backward movement so that the treatment tool 200 is easily operatedby a surgeon.

In the overtube 300 of the present embodiment, the endoscope insertionpart 102 and the treatment tool insertion part 202 are coupled by theslider 400. Thus, there is a concern that the positions of the endoscopeinsertion part 102 in the upward-downward direction and in theleftward-rightward direction and the rotational angle thereof around theaxis may fluctuate due to the rotational operation or the like of thetreatment tool insertion part 202.

However, since operations other than the forward and backward movementof the slider 400 are restricted as described above, the treatment toolinsertion part 202 can be rotated around the axis without changing thepositions of the endoscope insertion part 102 in the upward-downwarddirection and in the leftward-rightward direction and the rotationalangle thereof around the axis, and the degree of freedom (five degreesof freedom) required for the operation of forceps operation is obtained.In addition, the five degrees of freedom of the operation of the forcepsare the movement of the forceps with respect to an internal organ, andindicate five movements of the forceps including the movements of theforceps in the longitudinal direction, the transverse direction, and theforward and backward movement direction, the rotation of the forceps,and the opening/closing operation of the forceps.

(Operating Conditions of Slider)

Next, the operating conditions of the slider 400 will be described.Here, forces that act on the respective members related to the operationof the slider 400 are defined as follows.

A force with which the pressure-contact member 426 of theendoscope-coupled part 420 fixes the endoscope insertion part 102 at afixed position of the outer peripheral surface thereof is referred to asa fixing force for fixing the slider body 402 to the endoscope insertionpart 102, and the magnitude of the fixing force (the fixing force forfixing the endoscope insertion part 102 at the fixed position in theaxial direction) with respect to the axial direction (forward-rearwarddirection) is defined as F1.

Similarly, a force with which the pressure-contact member 446 of thesleeve 440 in the treatment tool-coupled part 422 fixes the treatmenttool insertion part 202 at a fixed position of the outer peripheralsurface thereof is referred to as a fixing force for fixing the sleeve440 to the treatment tool insertion part 202, and the magnitude of thefixing force with respect to the axial direction (forward-rearwarddirection) is defined as F2.

Meanwhile, a frictional force received from the valve member 346 whenthe endoscope insertion part 102 moves forward and backward is definedas F3, and a frictional force received from the valve member 348 whenthe treatment tool insertion part 202 moves forward and backward isdefined as F4.

Additionally, a frictional force received from a peripheral member whenthe sleeve 440 moves forward and backward with respect to the sliderbody 402 is defined as F5, and a frictional force received from theperipheral member when the slider body 402 moves forward and backwardwith respect to the overtube body 320 is defined as F6.

(a) Conditions in which Endoscope and Treatment Tool are Interlockedwith Each Other when Forward and Backward Movement Width of TreatmentTool is Large

When the treatment tool insertion part 202 has been moved forward andbackward (when the treatment tool insertion part has been markedly movedforward and backward), as conditions in which the endoscope insertionpart 102 and the treatment tool insertion part 202 are integrally movedforward and backward via the slider 400, the fixing forces F1 and F2,and the frictional force F3 satisfy the following conditions (1) and(2).F1>F3  (1)F2>F3  (2)

Accordingly, if the sleeve 440 reaches the rear end or the front end ofthe movable range thereof with respect to the slider body 402 asillustrated in FIG. 12 or 13 when the treatment tool insertion part 202has been moved forward and backward, the sleeve 440 receives thefrictional force F3 of the valve member 346 via the slider body 402 andthe endoscope insertion part 102. In this case, since the endoscopeinsertion part 102 and the slider body 402 are coupled by a largerfixing force F1 than the frictional force F3 and the treatment toolinsertion part 202 and the sleeve 440 are coupled by a larger fixingforce F2 than the frictional force F3, the slider body 402 moves forwardand backward in an interlocking manner with the forward and backwardmovement of the treatment tool insertion part 202, and the endoscopeinsertion part 102 moves forward and backward in an interlocking mannerwith the forward and backward movement of the slider body 402.

Therefore, when the treatment tool insertion part 202 has been movedforward and backward, there is no case where, due to the frictionalforce of the valve member 346, the engagement position of the endoscopeinsertion part 102 engaged with the slider body 402 shifts and theengagement position of the treatment tool insertion part 202 engagedwith the sleeve 440 also shifts.

In addition, when the treatment tool insertion part 202 has been movedforward and backward, as a condition for moving the slider body 402forward and backward with respect to the overtube body 320 in aninterlocking manner with this operation, the fixing force F2 and thefrictional force F6 satisfy the following condition (3).F2>F6  (3)

Similarly, when the endoscope insertion part 102 has been moved forwardand backward, in order to move the endoscope insertion part 102 and thetreatment tool insertion part 202 forward and backward integrally viathe slider 400, the fixing forces F1 and F2, and the frictional force F4satisfy the following conditions (4) and (5).F1>F4  (4)F2>F4  (5)

Additionally, when the endoscope insertion part 102 has been movedforward and backward, as a condition for moving the slider body 402forward and backward with respect to the overtube body 320 in aninterlocking manner with this operation, the fixing force F1 and thefrictional force F6 satisfy the following condition (6).F1>F6  (6)

(b) Conditions in which Endoscope and Treatment Tool are not Interlockedwith Each Other when Forward and Backward Movement Width of TreatmentTool is Small

When the treatment tool insertion part 202 has been moved forward andbackward with a small width, as a condition for moving only thetreatment tool insertion part 202 forward and backward without movingthe endoscope insertion part 102 forward and backward as illustrated inFIG. 11, the frictional forces F3, F5, and F6 satisfy the followingcondition (7).F3+F6>F5  (7)

As a result, as illustrated in FIG. 11, when the movement width of thetreatment tool insertion part 202 is small, the endoscope insertion part102 does not move, and when the forward and backward movement width ofthe treatment tool insertion part 202 is large, the endoscope insertionpart 102 moves. That is, when the forward and backward movement width ofthe treatment tool insertion part 202 is small, the sleeve 440 movesforward and backward only within the slider body 402, and the sliderbody 402 itself does not move with respect to the overtube body 320.Thus, the endoscope insertion part 102 does not move forward andbackward in the axial direction (forward-rearward direction).

In addition, since F6 is considered to be substantially 0 when thefrictional resistance of the slider body 402 with respect to theovertube body 320 is small enough to be ignored compared to thefrictional force between the endoscope insertion part 102 and the valvemember 346, the condition (7) becomes F3>F5.

On the other hand, when the forward and backward movement width of thetreatment tool insertion part 202 is large, the sleeve 440 moves forwardand backward within the slider body 402, is struck against the distalend side or the base end side of the slider body 402 and moves theslider body 402 itself with respect to the overtube body 320. Thus, theendoscope insertion part 102 coupled to the slider body 402 also movesforward and backward.

(c) Conditions for Adjustment of Length of Treatment Tool Insertion Part202

As a condition for adjusting the length of the treatment tool insertionpart 202 while gripping the endoscope 100 and the treatment tool 200, itis preferable that the fixing force F1 and F2 satisfy the followingcondition (8).F1>F2  (8)

Accordingly, even when the treatment tool insertion part 202 has beenmoved forward and backward using the overtube body 320 or even when thetreatment tool insertion part 202 has been moved forward and backwardusing the endoscope insertion part 102, the engagement position of thetreatment tool insertion part 202 using the slider body 402 can bechanged without changing the engagement position of the endoscopeinsertion part 102 engaged with the slider body 402.

When the length of the treatment tool insertion part 202 is adjusted bymoving the treatment tool insertion part 202 forward and backward usingthe overtube body 320, frictional forces are generated between thesleeve 440 and the treatment tool insertion part 202 and between thevalve member 348 and the treatment tool insertion part 202. Thus, theoperating force required for the forward and backward movement of thetreatment tool insertion part 202 is F2+F4. Therefore, in order to allowa surgeon to perform such an adjustment operation without feelingstress, it is desirable that the fixing force F2 and the frictionalforce F4 satisfy the following condition (9).F2+F4<10 N (N is Newtons)  (9)

Meanwhile, when the length of the treatment tool insertion part 202 isadjusted by moving the treatment tool insertion part 202 forward andbackward using the endoscope insertion part 102, if F4>F3 is satisfied,the same frictional forces as above are generated. Thus, it is desirableto satisfy Expression (9). If F3<F4 is satisfied, frictional forces aregenerated between the sleeve 440 and the treatment tool insertion part202 and between the valve member 346 and the endoscope insertion part102. Thus the operating force required for the forward and backwardmovement of the treatment tool insertion part 202 is F2+F3. Therefore,in order to allow a surgeon to perform such an adjustment operationwithout feeling stress, it is desirable that the fixing force F2 and thefrictional force F3 satisfy the following condition (10).F2+F3<10 N (N is Newtons)  (10)

The invention is effective not only when both of the condition (9) andthe condition (10) are satisfied but also when only any one of theseconditions is satisfied.

In addition, even when the fixing forces F1 and F2 satisfy the followingExpression (11), the length of the treatment tool insertion part 202 canbe adjusted. In this case, however, the engagement position between theendoscope insertion part 102 and the slider body 402 may move, and thepositional adjustment between the slider body 402 and the endoscopeinsertion part 102 may be separately required.F1<F2  (11)

In order to allow a surgeon to perform such an adjustment operationwithout feeling stress, it is desirable that the fixing force F1 and thefrictional force F3 or F4 satisfy the following condition (12) or (13).F1+F4<10 N (N is Newtons)  (12)F1+F3<10 N (N is Newtons)  (13)

(d) Conditions for Securing Excellent Operability

As a condition in which a surgeon can perform the forward and backwardmovement of the treatment tool insertion part 202 without feelingstress, it is preferable that the frictional forces F3, F4, and F6satisfy the following condition (14).F3+F4+F6<10 N (N is Newtons)  (14)

In this way, by setting the required operating force (F3+F4+F6) when asurgeon moves the treatment tool insertion part 202 forward and backwardmarkedly, a surgeon can secure excellent operability without feelingstress.

(e) Conditions for Preventing Overtube from Shifting with Respect toBody Wall

As a condition in which the overtube 300 (overtube body 320) isprevented from shifting due to the forward and backward movement of thetreatment tool insertion part 202, if the fixing force of the overtube300 in the forward-rearward direction (axial direction) with respect toa body wall is defined as Ft, the fixing force Ft and the frictionalforces F3 and F4 satisfy the following condition (15).Ft>F3+F4  (15)

Accordingly, even if the treatment tool insertion part 202 has beenmoved forward and backward, the overtube 300 (overtube body 320)inserted into a body wall is fixed in a stable state without shifting.Thus, it is possible to secure excellent operability.

(Other Forms of Slider)

In the above overtube 300, a supporting mechanism of the slider 400adapted to be capable of moving the slider 400 forward and backward onlyin the forward-rearward direction with respect to the overtube body 320is not limited to the above form.

FIG. 15 is a sectional view illustrating another form of the overtube300 by the section orthogonal to the reference axis 300 a. In addition,the same reference signs will be given to constituent elements of thesame or similar actions as those of the above form, and the descriptionthereof will be omitted.

In the form illustrated in this drawing, guide rods 470 and 472, whichare laid from the base end (base end cap 340) to the distal end (distalend cap 360), are arranged along the direction of the reference axis 300a at the upper part and the lower part within the lumen 324 of theovertube body 320.

Meanwhile, guide holes 474 and 476, which penetrate from the base end tothe front end, are formed at the upper part and the lower part of theslider body 402 of the slider 400.

The guide rods 470 and 472 are respectively inserted through the guideholes 474 and 476, and the slider 400 is supported within the lumen 324.

Accordingly, the slider 400 is supported so as to be movable forward andbackward only in the forward-rearward direction with respect to theovertube body 320.

FIG. 16 is a sectional view illustrating still another form of theovertube 300 by the section orthogonal to the reference axis 300 a. Inaddition, the same reference signs will be given to constituent elementsof the same or similar actions as those of the above form, and thedescription thereof will be omitted.

As illustrated in this drawing, the inner peripheral surface of theovertube body 320 (outer wall 322), that is, the outer shape of thelumen 324, is formed in an elliptical shape in the section orthogonal tothe reference axis 300 a.

Meanwhile, the slider 400 is formed so that the outer peripheral surfaceof the slider body 402 that is a frame body has a shape along an ellipseof the same shape as the lumen 324 in the section orthogonal to thereference axis 300 a and the outer peripheral surface of the slider body402 comes in contact with or approaches the inner peripheral surface ofthe overtube body 320.

Accordingly, the slider 400 is supported so as to be movable forward andbackward only in the forward-rearward direction with respect to theovertube body 320.

In addition, the shape of the slider is not limited to this, and theshape of the inner peripheral surface of the overtube body 320 and theshape of the slider body 402 in the section orthogonal to the referenceaxis 300 a only has to be a combination of non-rotatable shapes. Forexample, in the forms illustrated in FIGS. 7 and 15, if the shape of theinner peripheral surface of the overtube body 320 is fonned in anelliptical shape as illustrated in FIG. 16 and the inner peripheralsurface of the overtube body 320 is circumscribed on the slider body402, similar to the form of FIG. 16, special guide means, such as theform of the protruding strips 408 and 410, the guide plates 374 and 376in the form of FIG. 7 and the guide rods 470 and 472 and the guide holes474 and 476 in the form of FIG. 15, can be made unnecessary.

(Description of Inner Needle)

Next, an inner needle 500 to be used after being mounted on the overtube300 when the overtube 300 is inserted into a body wall will bedescribed.

FIGS. 17 and 18 are respectively perspective views illustrating a statewhere the inner needle 500 has been mounted on the overtube 300 from thefront upper left and from the rear lower left, and FIG. 19 is aperspective view illustrating only the inner needle 500 from the frontlower left. In addition, the relationship of front and rear, left andright, and up and down of the inner needle 500 follows the relationshipof front and rear, left and right, and up and down of the overtube 300when being mounted on the overtube 300 as illustrated in FIG. 17.

As illustrated in these drawings, the inner needle 500 is constituted oftwo rod parts 502 and 504 that are formed in an elongated shape, distalend parts 506 and 508 that are respectively formed at the distal ends ofthe rod parts 502 and 504, and a head part 510 that is provided on thebase end sides of the rod parts 502 and 504.

The rod part 502 (first rod part) has a diameter equal to or smallerthan the external diameter of the above-described endoscope insertionpart 102, and is formed with a size such that the rod part is insertablethrough the endoscope insertion passage 306. As illustrated in FIGS. 17and 18, when the inner needle 500 is mounted on (incorporated into) theovertube 300, the rod part 502 is arranged so as to be inserted throughthe endoscope insertion passage 306 of the overtube 300.

Additionally, the rod part 502 is formed to be slightly longer than thelength of the overtube 300 (endoscope insertion passage 306) in theforward-rearward direction, and when the inner needle 500 has beenmounted on the overtube 300, the distal end part 506 of the rod part 502protrudes by a predetermined length from the endoscope delivery opening312.

The rod part 504 (second rod part) has a diameter equal to or smallerthan the external diameter of the above-described treatment toolinsertion part 202, and is formed with a size such that the rod part isinsertable through the treatment tool insertion passage 308. Asillustrated in FIGS. 17 and 18, when the inner needle 500 is mounted onthe overtube 300, the rod part 504 is arranged so as to be insertedthrough the treatment tool insertion passage 308 of the overtube 300.

Additionally, the rod part 504 is formed to be slightly longer than thelength of the overtube 300 (treatment tool insertion passage 308) in theforward-rearward direction, and when the inner needle 500 has beenmounted on the overtube 300, the distal end part 508 of the rod part 504protrudes by a predetermined length from the treatment tool deliveryopening 316.

Although the distal end parts 506 and 508 are formed in a curved surfaceshape and are configured to be dull so that no edge is formed (that is,in a rounded non-edge shape), the distal end parts are adapted to becapable of penetrating a body wall easily.

The head part 510 has a head part body 512 and a locking lever 514.

The head part body 512, as illustrated in FIGS. 18 and 19, has a shapesurrounded by a side surface 522 along a column surface having an axis520 extending in the forward-rearward direction in parallel with the rodparts 502 and 504 as a center having a diameter that approximatelycoincides with the external diameter of the base end cap 340 of theovertube 300, a lower surface 524 along a plane which is parallel to theaxis 520 (parallel to the forward-rearward direction and theleftward-rightward direction) and which intersects the column surfacealong which the side surface 522 runs, and a rear end surface 526 and afront end surface 528 along a plane orthogonal to the axis 520.

In addition, the axis 520 is arranged coaxially with the reference axis300 a (not illustrated) of the overtube 300 in a state where the innerneedle 500 has been mounted on the overtube 300.

The front end surface 528 of the head part body 512 has the base endsides of the rod parts 502 and 504 fixed thereto, and the side surface522 of the head part body 512 has the locking lever 514 provided alongthe direction (forward-rearward direction) of the axis 520 at a centralpart (topmost part) thereof in the circumferential direction.

The locking lever 514 is a constituent element of a fixing mechanismthat detachably fixes the head part 510 of the inner needle 500 to theovertube 300, is formed in an elongated plate shape extending along thedirection of the axis 520 (refer to FIG. 17), and is supported by thehead part body 512 so as to be turnable in such an orientation that afront end part and a rear end part are opposite to each other in theupward-downward direction with the vicinity of the center in thedirection of the axis 520 as a fulcrum.

A locking claw 532 (refer to FIG. 19) is provided to protrude from alower surface side of a distal end part of the locking lever 514, andthe locking claw 532, as illustrated in FIGS. 3 and 5, has such a shapethat the locking claw is fitted to a locking hole 534 provided in thebase end cap 340.

Additionally, a biasing member, such as a coil spring, is arranged atthe head part body 512 at a position on a lower surface side of a baseend part of the locking lever 514, and the locking lever 514 is biasedso that the rear end part faces up and the front end part faces down.

(Action when Inner Needle is Mounted)

According to the inner needle 500 configured as above, if the rod parts502 and 504 of the inner needle 500 are respectively inserted into theendoscope insertion passage 306 and the treatment tool insertion passage308 from the endoscope insertion opening 310 and the treatment toolinsertion opening 314, respectively, of the overtube 300, as illustratedin FIG. 20, the head part 510 of the inner needle 500 approaches thebase end cap 340 of the overtube 300.

Then, if the inner needle 500 is further inserted, as illustrated inFIGS. 17 and 18, the front end surface 528 of the head part body 512abuts against the base end surface 302 of the overtube 300 (base end cap340), and the locking claw 532 of the locking lever 514 is fitted to thelocking hole 534 of the base end cap 340 and is brought into a statewhere the inner needle 500 has been mounted on (fixed to) the overtube300.

In this case, the distal end parts 506 and 508 of the rod parts 502 and504 of the inner needle 500 are arranged so as to protrude by apredetermined length from the distal end of the overtube 300.

Meanwhile, if the base end part of the locking lever 514 is pressed in astate where the inner needle 500 has been mounted on the overtube 300,the locking claw 532 can be removed from the locking hole 534 of thebase end cap 340, and if the inner needle 500 is pulled out to the handside in that state, the inner needle 500 can be detached from theovertube 300.

Additionally, as described above, the head part body 512 of the innerneedle 500 has such a shape that a lower side of a columnar member iscut out by the lower surface 524. That is, the head part body 512 isprovided with a cutout part formed by cutting out a portion thatinterferes with the air supply connector 318 when the inner needle 500has been mounted on the overtube 300.

Accordingly, the front end surface 528 of the head part body 512 can bemade to abut against the base end surface 302 without interfering withthe air supply connector 318 provided to protrude from the base endsurface 302 of the overtube 300 (base end cap 340) as illustrated inFIG. 18 when the inner needle 500 has been mounted on the overtube 300,and the inner needle 500 can be mounted on the overtube 300 in a stablestate.

In addition, the invention is not limited to the above form, and thehead part body 512 only has to have the cutout part formed by cuttingout the portion of the head part body 512 that interferes with at leastthe air supply connector 318 when the inner needle 500 has been mountedon the overtube 300. Additionally, since the rotation of the head partbody 512 is restricted with respect to the overtube 300 by the rod parts502 and 504, the head part body does not interfere with the air supplyconnector 318.

<Operation Method of Endoscopic Surgical Device>

Next, an example of operation methods using the endoscopic surgicaldevice 10 of the present embodiment will be described.

FIGS. 21A to 25B are explanatory views illustrating a situation in whichthe endoscopic surgical device 10 of the present embodiment is operated.

FIGS. 21A to 21C are views illustrating a situation in which theovertube 300 is inserted into a body wall.

FIGS. 22A to 23B are views illustrating a situation in which thetreatment tool insertion part 202 is pushed into an affected part sidewithin a body cavity from the hand side.

FIGS. 24A to 25B are views illustrating a situation in which thetreatment tool insertion part 202 is pulled to the hand side from theaffected part side within the body cavity.

First, as a preparation process for starting the operation of theendoscopic surgical device 10, the overtube 300 is inserted into a skinincision part (incised wound) formed in a body wall in a state where theinner needle 500 is inserted into the endoscope insertion passage 306and the treatment tool insertion passage 308 of the overtube 300, andthe overtube 300 is inserted into the body cavity like a statedesignated by reference sign 1000 of FIG. 21A.

Next, the inner needle 500 is extracted from the endoscope insertionpassage 306 and the treatment tool insertion passage 308 (the innerneedle 500 is removed from the overtube 300), and one end part of theair supply tube 122 is connected to the air supply connector 318 of theovertube 300 like a state designated by reference sign 1002 of FIG. 21B.The other end part is connected to the pneumoperitoneum device 120.Then, pneumoperitoneum gas is delivered from the pneumoperitoneum device120, and the pneumoperitoneum gas is injected into the body cavitythrough the air supply tube 122 and the overtube 300.

Next, the endoscope insertion part 102 is inserted into the endoscopeinsertion passage 306 from the endoscope insertion opening 310 of theovertube 300, and the distal end of the endoscope insertion part 102 isled out from the endoscope delivery opening 312.

In this case, the endoscope insertion part 102 has the endoscope-coupledpart 420 of the slider 400 inserted therethrough, and is coupled to theslider body 402 as described above. Accordingly, the endoscope insertionpart 102 and the slider 400 are brought into a state where they moveintegrally.

Subsequently, the treatment tool insertion part 202 is inserted into thetreatment tool insertion passage 308 from the treatment tool insertionopening 314 of the overtube 300, and the distal end (treatment part 206)of the treatment tool insertion part 202 is led out from the treatmenttool delivery opening 316.

In this case, the treatment tool insertion part 202 has the sleeve 440of the treatment tool-coupled part 422 of the slider 400 insertedtherethrough, and is coupled to the sleeve 440 as described above.Accordingly, the treatment tool insertion part 202 and the sleeve 440are brought into a state where they move integrally.

If the preparation step is performed in this way, a state where theoperation of the endoscopic surgical device 10 is operable is broughtabout like a state designated by reference sign 1004 of FIG. 21C.

In addition, the distal end position of the endoscope insertion part 102is arranged behind at least the distal end position of the treatmenttool insertion part 202 so that the situation of the treatment part 206at the distal end of the treatment tool insertion part 202 can beobserved by the endoscope 100. Additionally, the procedure of insertingthe endoscope insertion part 102 and the treatment tool insertion part202 into the overtube 300 is not limited to the above-described order,and the endoscope insertion part 102 may be inserted after the treatmenttool insertion part 202 is inserted.

Next, a case where the treatment tool insertion part 202 is pushed intothe affected part side within the body cavity from the hand side (a casewhere the treatment tool insertion part moves forward) will be describedwith reference to FIGS. 22A to 23B.

First, when the treatment tool insertion part 202 has been minutelydisplaced in the axial direction like a state designated by referencesign 1008 of FIG. 22B from a state designated by reference sign 1006 ofFIG. 22A (when a forward and backward movement of a small amplitude hasbeen performed), only the treatment tool insertion part 202 movesforward and backward, and the slider 400 does not move forward andbackward. Therefore, since the endoscope insertion part 102 does notmove forward and backward, the range of an observation image displayedon the monitor 112 does not change. For this reason, the size of anobject to be observed can be prevented from fluctuating according to theminute displacement of the treatment tool insertion part 202, a sense ofperspective can be suitably maintained, and a stable observation imagecan be obtained.

In contrast, when the treatment tool insertion part 202 has been largelydisplaced in the axial direction like a state designated by referencesign 1006 of FIG. 23B from a state designated by reference sign 1006 ofFIG. 23A that is the same state as reference sign 1010 of FIG. 22A (whena forward and backward movement of a large amplitude has beenperformed), the slider 400 moves forward and backward in an interlockingmanner with the forward and backward movement of the treatment toolinsertion part 202. In this case, since the endoscope insertion part 102moves forward and backward, the range of an observation image displayedon the monitor 112 is continuously changed so as to follow the forwardand backward movement of the treatment tool insertion part 202.Accordingly, since the size of an object to be observed changesaccording to the operation of the treatment tool 200, it is possible tosimply obtain an image desired by a surgeon.

Additionally, the same applies to a case where the treatment toolinsertion part 202 is pulled to the hand side from the affected partside within the body cavity (when the treatment tool insertion partmoves backward).

That is, when the treatment tool insertion part 202 has been minutelydisplaced in the axial direction like a state designated by referencesign 1014 of part (B) of FIG. 24 from a state designated by referencesign 1012 of part (A) of FIG. 24 (when a forward and backward movementof a small amplitude has been performed), only the treatment toolinsertion part 202 moves forward and backward, and the slider 400 doesnot move forward and backward. Therefore, since the endoscope insertionpart 102 does not move forward and backward, the range of an observationimage displayed on the monitor 112 does not change. For this reason, thesize of an object to be observed can be prevented from fluctuatingaccording to the minute displacement of the treatment tool insertionpart 202, a sense of perspective can be suitably maintained, and astable observation image can be obtained.

In contrast, when the treatment tool insertion part 202 has been largelydisplaced in the axial direction like a state designated by referencesign 1012 of part (B) of FIG. 25 from a state designated by referencesign 1012 of part (A) of FIG. 25 that is the same state as referencesign 1016 of part (A) of FIG. 24 (when a forward and backward movementof a large amplitude has been performed), the slider 400 moves forwardand backward in an interlocking manner with the forward and backwardmovement of the treatment tool insertion part 202. In this case, sincethe endoscope insertion part 102 moves forward and backward, the rangeof an observation image displayed on the monitor 112 is continuouslychanged so as to follow the forward and backward movement of thetreatment tool insertion part 202. Accordingly, since the size of anobject to be observed changes according to the operation of thetreatment tool 200, it is possible to simply obtain an image desired bya surgeon.

Although the endoscopic surgical device and the overtube related to theinvention has been described above in detail, the invention is notlimited to the above embodiments, and various improvements andmodifications may be made without departing from the scope of theinvention.

EXPLANATION OF REFERENCES

-   -   10: endoscopic surgical device    -   100: endoscope    -   102: endoscope insertion part    -   104: operating part    -   108: processor device    -   110: light source device    -   112: monitor    -   120: pneumoperitoneum device    -   122: air supply tube    -   200: treatment tool    -   202: treatment tool insertion part    -   204: operating part    -   206: treatment part    -   300: overtube    -   302: base end surface    -   304: distal end surface    -   306: endoscope insertion passage    -   306 a: endoscope insertion axis    -   308: treatment tool insertion passage    -   308 a: treatment tool insertion axis    -   310: endoscope insertion opening    -   312: endoscope delivery opening    -   314: treatment tool insertion opening    -   316: treatment tool delivery opening    -   318: air supply connector    -   320: overtube body    -   322: outer wall    -   324: lumen    -   340: base end cap    -   342, 344, 350: through-hole    -   346    -   348: valve member    -   360: distal end cap    -   362, 364: through-hole    -   370, 372: guide groove    -   374, 376: guide plate    -   400: slider    -   402: slider body    -   408, 410: protruding strip    -   420: endoscope-coupled part    -   422: treatment tool-coupled part    -   424: through-hole    -   426: pressure-contact member    -   428: pressure-contact member attachment part    -   431: side surface    -   440: sleeve    -   444: sleeve body    -   446: pressure-contact member    -   448, 450: through-hole    -   460: guide part    -   500: inner needle    -   502, 504: rod part    -   506, 508: distal end part    -   510: head part    -   512: head part body    -   514: locking lever    -   520: axis    -   532: locking claw    -   534: locking hole

What is claimed is:
 1. An endoscopic surgical device comprising: anendoscope that observes the inside of a body cavity; a treatment toolthat inspects or treats an affected part within the body cavity; and anovertube that guides the endoscope and the treatment tool into the bodycavity, wherein the overtube includes an endoscope insertion passagethat allows the endoscope to be inserted therethrough so as to bemovable forward and backward, a treatment tool insertion passage thatallows the treatment tool to be inserted therethrough so as to bemovable forward and backward, a first valve member that is provided inthe endoscope insertion passage and secures airtightness within the bodycavity, a second valve member that is provided in the treatment toolinsertion passage and secures the airtightness within the body cavity,and an interlocking member that is configured to be movable forward andbackward along the overtube, and has an endoscope-coupled part to becoupled to the endoscope inserted through the endoscope insertionpassage and a treatment tool-coupled part to be coupled to the treatmenttool inserted through the treatment tool insertion passage, and whereinfollowing formulas are satisfied when a fixing force for fixing theinterlocking member to the endoscope is defined as F1, a fixing forcefor fixing the interlocking member to the treatment tool is defined asF2, and a frictional force that the endoscope receives from the firstvalve member when the endoscope moves forward and backward is defined asF3:F1>F3F2>F3.
 2. The endoscopic surgical device according to claim 1, wherein afollowing formula is satisfied when a frictional force that thetreatment tool receives from the second valve member when the treatmenttool moves forward and backward is defined as F4, and a fixing force forfixing the overtube to the body wall in a forward and backward movementdirection is defined as Ft:Ft>F3+F4,
 3. The endoscopic surgical device according to claim 1,wherein a following formula is satisfied:F1>F2,
 4. The endoscopic surgical device according to claim 3, whereinin the interlocking member, the endoscope-coupled part includes anendoscope fixed region where the endoscope is fixed, and the treatmenttool-coupled part includes a treatment tool fixed region where thetreatment tool is fixed, and the endoscope fixed region is made longerthan the treatment tool fixed region.
 5. The endoscopic surgical deviceaccording to claim 1, wherein, when a frictional force that thetreatment tool receives from the second valve member when the treatmenttool moves forward and backward is defined as F4, either F2+F4<10Newtons or F2+F3<10 Newtons is satisfied in the case of F1>F2, andeither F1+F4<10 Newtons or F1+F3<10 Newtons is satisfied in the case ofF1<F2.
 6. The endoscopic surgical device according to claim 1, whereinthe interlocking member includes a dead zone where the forward andbackward movement of either the endoscope or the treatment tool does notinterlock with the movement of the other and a sensing zone where theforward and backward movement of either the endoscope or the treatmenttool interlocks with the movement of the other.
 7. The endoscopicsurgical device according to claim 1, wherein the treatment tool-coupledpart of the interlocking member includes a treatment tool-coupled membercoupled to the treatment tool, and the treatment tool-coupled member isprovided to be rotatable with respect to the interlocking member.
 8. Theendoscopic surgical device according to claim 1, wherein theinterlocking member includes a slider member that is coupled to theendoscope and moves forward and backward integrally with the endoscope,and a sleeve member that is coupled to the treatment tool and movesforward and backward integrally with the treatment tool, and wherein arange where the sleeve member is movable forward and backward withrespect to the slider member is limited.
 9. The endoscopic surgicaldevice according to claim 8, wherein the sleeve member is configured soas to be rotatable around an axis thereof with respect to the slidermember.
 10. The endoscopic surgical device according to claim 8, whereinthe slider member is configured so as to be non-rotatable around an axisthereof with respect to the overtube.
 11. An overtube which is to beinserted into a body cavity through a body wall, the overtubecomprising: an endoscope insertion passage that allows an endoscope forobserving the inside of the body cavity to be inserted therethrough soas to be movable forward and backward; a treatment tool insertionpassage that allows a treatment tool for inspecting or treating anaffected part within the body cavity to be inserted therethrough so asto be movable forward and backward; a first valve member that isprovided in the endoscope insertion passage and secures airtightnesswithin the body cavity; a second valve member that is provided in thetreatment tool insertion passage and secures the airtightness within thebody cavity; and an interlocking member that is configured to be movableforward and backward along the overtube, and has an endoscope-coupledpart to be coupled to the endoscope inserted through the endoscopeinsertion passage and a treatment tool-coupled part to be coupled to thetreatment tool inserted through the treatment tool insertion passage,wherein following formulas are satisfied when a fixing force for fixingthe interlocking member to the endoscope is defined as F1, a fixingforce for fixing the interlocking member to the treatment tool isdefined as F2, and a frictional force that the endoscope receives fromthe first valve member when the endoscope moves forward and backward isdefined as F3:F1>F3F2>F3.
 12. The overtube according to claim 11, wherein a followingformula is satisfied when a frictional force that the treatment toolreceives from the second valve member when the treatment tool movesforward and backward is defined as F4, and a fixing force for fixing theovertube to the body wall in a forward and backward movement directionis defined as Ft:Ft>F3+F4.
 13. The overtube according to claim 11, wherein a followingformula is satisfied:F1>F2.
 14. The overtube according to claim 13, wherein in theinterlocking member, the endoscope-coupled part includes an endoscopefixed region where the endoscope is fixed, and the treatmenttool-coupled part includes a treatment tool fixed region where thetreatment tool is fixed, and the endoscope fixed region is made longerthan the treatment tool fixed region.
 15. The overtube according toclaim 11, wherein, when a frictional force that the treatment toolreceives from the second valve member when the treatment tool movesforward and backward is defined as F4, either F2+F4<10 Newtons orF2+F3<10 Newtons is satisfied in the case of F1>F2, and either F1+F4<10Newtons or F1+F3<10 Newtons is satisfied in the case of F1<F2.
 16. Theovertube according to claim 11, wherein the interlocking member includesa dead zone where the forward and backward movement of either theendoscope or the treatment tool does not interlock with the movement ofthe other and a sensing zone where the forward and backward movement ofeither the endoscope or the treatment tool interlocks with the movementof the other.